Arthrofibrosis of the knee is a complication of injury or surgery where an excessive scar tissue response leads to painful restriction of knee motion.

Page updated October 2023 by Dr Sheila Strover (Clinical Editor)

normal knee, before onset of arthrofibrosis


The normal knee has soft tissue folds that are lubricated and allow movement

sites of arthrofibrosis in the knee


Inflammation triggers sticky adhesions gluing up the tissue folds

Advanced arthrofibrosis of the knee


Adhesions mature into scar tissue, which contracts and locks up the joint


The process of arthrofibrosis

The process is triggered by inflammation most commonly affecting the fat pad behind the patellar tendon. Then adhesions develop start to stick down the soft tissue folds of the suprapatellar pouch, posterior capsule and anterior interval underneath the tendon. This may result in flexion loss, extension loss or both. Matured scar tissue then contracts, closing the important spaces that normally allow movement, and pulling the kneecap right down (patella baja or infera), where every movement is painful.

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Symptoms of early arthrofibrosis

Problems due to arthrofibrosis are uncommon but are usually consequent on significant knee surgery such as multiligament reconstruction or total knee replacement, or a bad knee injury where the joint has had to be immobilised, particularly where there may have been a bleed inside the knee (haemarthrosis), and painful swelling of the joint. The patient may have felt confident starting rehabilitation exercises but then may have experienced progressive problems bending the knee, and these early attempts may be excessively painful. 'Pushing through the pain' may simply make things much worse, triggering more inflammation and swelling, and further limiting range of motion. The joint may feel warm to the touch.

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Symptoms of advanced arthrofibrosis and patella baja

As the soft tissues behind and below the kneecap become involved in the scar tissue process, the kneecap may be pulled into an abnormally low position (patella baja or patella infera) which may result in considerable pain trying to walk, and the knee may be most comfortable in a slightly bent position.

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Rehabilitation issues with arthrofibrosis

Early range of motion problems can be reversed with empathetic management - ideally patellar mobilisation and range of motion exercises in combination with adequate pain relief - without pushing the joint into painful inflammation that makes things worse. Manipulation under anaesthesia may help to break adhesions before they become permanent scar tissue. Advanced arthrofibrosis with marked knee stiffness may need surgical lysis of adhesions to regain range of motion, in combination with specialist pain management and physiotherapy.

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Internal scarring

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Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...

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Peer-reviewed articles -

Arthrofibrosis library of excerpts

Arthrofibrosis library


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eBook on patella baja in relation to arthrofibrosis

eBook - Arthrofibrosis and patella baja

by Dr Sheila Strover (Clinical Editor)

eBook explaining how the patella can become intimately involved in the arthrofibrosis process. Free to download.